The invention is related to a digital transmission system comprising a transmitter having a first source for generating in response to digital symbols a first voltage with respect to a reference voltage on a first wire of a transmission line, a second source for generating a second voltage with respect to said reference voltage on a second wire of the transmission line, said second voltage having an opposite phase with respect to the first voltage, the transmission system further comprises at least one receiver coupled to said transmission line, having a detector for deriving digital symbols from the voltage difference between the first and second wire.
The invention is further related to a transmitter, a receiver and a transceiver for such a transmission system.
A transmission system according to the preamble is known from the book "Digital Integrated Electronics" by H. Taub and D. Schilling, published by McGraw-Hill, 1977, ISBN 0-07-085788-1.
Transmission systems according to the preamble can be used in local area networks, in several bus systems, and the local loop area of a digital telephone system. In the known transmission system, a first end of a transmission line consisting of two wires is connected to a transmitter. A first source is connected to a first wire of the transmission line, and a second source is connected to a second wire of the transmission line. The signals generated by the first and second source are opposite in phase.
The receiver being connected to a second end of the transmission line is provided with a detector connected to the first wire and the second wire of the transmission line for deriving digital symbols from the voltage difference between the first wire and the second wire. Because the first and the second source generate voltages having opposite phases the information to be transmitted can be derived from the voltage difference between the two wires. This reduces the vulnerability of the transmission system to electromagnetic interference, resulting in an increase of electromagnetic compatibility (EMC) properties.
In the known transmission system no transmission is possible if a short circuit arises between the first wire and the second wire, so the complete transmission system will fail.